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Re: Changing a DPMI host, but keeping the DOS extender

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Rod Pemberton <do_not_have@notemailntt.cmm> wrote:
>E.g., there is a DOS Extender called U7WIN9X that allowed Ultima 7 or 8 to
>run.  Apparently, it wouldn't execute with EMS.  It emitted a warning and
>exited.  U7RUN.COM blocked the call detecting EMS so it would execute.

U7WIN9X wasn't a DOS extender and didn't work by disabling the dection of
EMS.  If I remember correctly it worked through a combination of patches
to the executable and a VxD that handled the faults that resulted from
how Ultima 7 tried to access memory using 32-bit offsets in real mode
(aka "unreal mode").

>I haven't had an EMS (or VCPI) driver installed in years.

You'll need to use EMS or UMBs if you want to use Rugxulo's trick
or install TSR to prevent the detection of VCPI.  DOS32/A checks the
procesor's CR0 register first.  If the PE (Protected Mode Enable) bit
isn't already set then it doesn't need to use VCPI or DPMI and doesn't
bother to check to see if they are available.  It simply enters protected
mode directly by setting the PE bit in CR0.

>So, is EMS really needed?  You might try disabling it and see how
>much of what you've got actually runs without it.  I'd guess that the
>number of programs which actually *require* only EMS and/or VCPI must be
>really small.  Most likely, I'd assume these applications were really old.

Rugxulo said he was no longer using EMS (or UMBs) by default anymore,
but before DOS4GW started being used in games, most of them required EMS.

					Ross Ridge

-- 
 l/  //	  Ross Ridge -- The Great HTMU
[oo][oo]  rridge@csclub.uwaterloo.ca
-()-/()/  http://www.csclub.uwaterloo.ca/~rridge/ 
 db  //	  

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Thread

Changing a DPMI host, but keeping the DOS extender "Rod Pemberton" <do_not_have@notemailntt.cmm> - 2012-05-19 20:08 -0400
  Re: Changing a DPMI host, but keeping the DOS extender Rugxulo <rugxulo@gmail.com> - 2012-05-19 19:07 -0700
    Re: Changing a DPMI host, but keeping the DOS extender "Rod Pemberton" <do_not_have@notemailntt.cmm> - 2012-05-20 05:38 -0400
      Re: Changing a DPMI host, but keeping the DOS extender Rugxulo <rugxulo@gmail.com> - 2012-05-20 09:15 -0700
        Re: Changing a DPMI host, but keeping the DOS extender "Rod Pemberton" <do_not_have@notemailntt.cmm> - 2012-05-20 20:46 -0400
          Re: Changing a DPMI host, but keeping the DOS extender Rugxulo <rugxulo@gmail.com> - 2012-05-21 16:26 -0700
            Re: Changing a DPMI host, but keeping the DOS extender "Rod Pemberton" <do_not_have@notemailntt.cmm> - 2012-05-22 03:39 -0400
              Re: Changing a DPMI host, but keeping the DOS extender Rugxulo <rugxulo@gmail.com> - 2012-05-22 08:41 -0700
                Re: Changing a DPMI host, but keeping the DOS extender Rugxulo <rugxulo@gmail.com> - 2012-05-22 16:14 -0700
                Re: Changing a DPMI host, but keeping the DOS extender "Rod Pemberton" <do_not_have@notemailntt.cmm> - 2012-05-24 15:38 -0400
                Re: Changing a DPMI host, but keeping the DOS extender Rugxulo <rugxulo@gmail.com> - 2012-05-24 14:06 -0700
                Re: Changing a DPMI host, but keeping the DOS extender Ross Ridge <rridge@csclub.uwaterloo.ca> - 2012-05-25 02:14 -0400
                Re: Changing a DPMI host, but keeping the DOS extender Rugxulo <rugxulo@gmail.com> - 2012-05-25 15:55 -0700
                Re: Changing a DPMI host, but keeping the DOS extender Ross Ridge <rridge@csclub.uwaterloo.ca> - 2012-05-25 21:42 -0400
                Re: Changing a DPMI host, but keeping the DOS extender Ross Ridge <rridge@csclub.uwaterloo.ca> - 2012-05-25 22:06 -0400
                Re: Changing a DPMI host, but keeping the DOS extender Rugxulo <rugxulo@gmail.com> - 2012-05-25 23:03 -0700
                Re: Changing a DPMI host, but keeping the DOS extender "Rod Pemberton" <do_not_have@notemailntt.cmm> - 2012-05-26 07:33 -0400
                Re: Changing a DPMI host, but keeping the DOS extender Ross Ridge <rridge@csclub.uwaterloo.ca> - 2012-05-26 20:10 -0400
                Re: Changing a DPMI host, but keeping the DOS extender "Harry Vaderchi" <admin@127.0.0.1> - 2012-05-28 07:38 +0100
  Re: Changing a DPMI host, but keeping the DOS extender Ross Ridge <rridge@csclub.uwaterloo.ca> - 2012-05-20 19:20 -0400

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